Improved the filename validation

components/EditorNavigation.tsx

@@ -96,33 +96,26 @@ const EditorNavigation = ({ showWat }: { showWat?: boolean }) => {
       }
 
       // check for illegal characters
-      const ILLEGAL_REGEX = /[/]/gi;
-      const ALPHA_NUMERICAL_REGEX = /[^A-Za-z0-9._-]+/g;
-      if (
-        filename.match(ILLEGAL_REGEX) ||
-        // Allow only a-z, A-Z, 0-9, ".", "-" and "_"
-        filename.match(ALPHA_NUMERICAL_REGEX)
-      ) {
-        return { error: "Filename contains illegal characters" };
+      const ALPHA_NUMERICAL_REGEX = /^[\w,\s-]+\.[A-Za-z0-9]{1,4}$/g;
+      if (!filename.match(ALPHA_NUMERICAL_REGEX)) {
+        return {
+          error: `Filename can contain only characters from a-z, A-Z, 0-9, "_" and "-" and it needs to have file extension (e.g. ".c")`,
+        };
       }
-      // More checks in future
       return { error: null };
     },
     [snap.files]
   );
   const handleConfirm = useCallback(() => {
     // add default extension in case omitted
-    let _filename = filename.includes(".")
-      ? filename
-      : filename + DEFAULT_EXTENSION;
-    const chk = validateFilename(_filename);
-    if (chk.error) {
+    const chk = validateFilename(filename);
+    if (chk && chk.error) {
       setNewfileError(`Error: ${chk.error}`);
       return;
     }
 
     setIsNewfileDialogOpen(false);
-    createNewFile(_filename);
+    createNewFile(filename);
     setFilename("");
   }, [filename, setIsNewfileDialogOpen, setFilename, validateFilename]);